Method and apparatus for incinerating refuse

ABSTRACT

Refuse is incinerated by advancing it longitudinally within an externally heated rotating furnace and utilizing the combustible gases emanating from the refuse to supply part of the fuel used to heat the furnace. The invention includes apparatus for use in carrying out this process.

United States Patent [1 1 Jaget, deceased et al.

[ Jan. 15, 1974 METHOD AND APPARATUS FOR INCINERATING REFUSE Inventors: Jean Jaget, deceased, late of 34, rue

Moliere, Montreuil, France; by Pierre Jaget, legal representative, 20 rue Ramponeau, Paris, France Filed: Feb. 15, 1972 Appl. No.: 226,626

0.8. CI. 110/14, 110/11 Int. Cl. F23g 5/06 Field of Search 110/8 R, 14, 11

References Cited UNITED STATES PATENTS Wcnger 110/14 2,127,328 8/1938 Egan llO/14 1,727,036 9/1939 Rank et al.

2,238,161 4/1941 Drew et al.

3,098,458 7/1963 Lantz, Jr

3,362,887 l/1968 Rodgers llO/ll X Primary Examinerl(enneth W. Sprague Att0rney-Joseph F. Brisebois et al.

[57] ABSTRACT Refuse is incinerated by advancing it longitudinally within an externally heated rotating furnace and utilizing the combustible gases emanating from the refuse to supply part of the fuel used to heat the furnace. The invention includes apparatus for use in carrying out this process.

12 Claims, 4 Drawing Figures PATENIEB JAN 15 m4 SHEET 3 OF 3 Wm mm mm Fw ww mv METHOD AND APPARATUS FOR INCINERATING REFUSE It is often necessary to destroy refuse of various sorts by incinerating it in an apparatus comprising burners which provide the heat necessary for the incineration. It is obvious that, in such incinerating devices, it is desirable, on the one hand, to produce adequate incineration of the refuse regardless of the nature of this refuse and, on the other hand, to reduce to the extent possible the amount of heat required to produce adequate incineration.

Incinerating devices have already been suggested which comprise a stationary furnace having at least one wall zone heated by burners. Such furnaces have, in general, a substantially flat lower wall, which is the one heated. In such furnaces the refuse is introduced laterally or perpendicularly onto a heated lower plate. It has been found that, in all cases, some packing of the refuse introduced into the furnace takes place and this is prejudicial to adequate incineration of all the refuse. It has also been found that the packing is especially troublesome in those incinerators in which the refuse is introduced perpendicularly onto a heated plate in the furnace. Moreover, in such incinerators, the gas resulting from the gasification of the refuse bursts into flame as it leaves the furnace and mixes with preheated air. A ventilator ensures the exhaustion of both the air and the gasification gases from the refuse in an arrangement such that this ventilator is traversed by the gas which has just been burned, the temperature of which is sufficiently high to pose substantial problems with respect to the strength of the ventilator. Finally, in such incinerators, the gasification gases are extracted through the upper part of the furnace and consequently can not furnish by their combustion any part of the calories used to heat the lower plate of the furnace so that the combustion calories of this gas are lost so far as heating of the furnace is concerned. They may, nevertheless, be used for pre-drying the refuse being introduced, when this refuse is introduced perpendicularly onto the heating plate of the furnace.

It is the object of the present invention to provide an incinerating process and an incinerator for refuse adapted to be used in carrying out said process in which these disadvantages are avoided.

In the apparatus according to the invention there is no compaction of the refuse, the gases resulting from the gasification of the refuse are used to heat the furnace, and the passage of burning gases through the ventilator for circulating air and extracting burned gases is prevented.

It is an object of the present invention to provide a process for the incineration of refuse which is essentially characterized by the fact that the refuse is intro duced at one end of a cylindrical or prismatic furnace which is rotated about its own axis, the refuse is ad vanced along the axis of the furnace by any suitable means, the lateral wall of the furnace is heated by burners, for example, the cinders formed by the incinerated refuse are extracted from the end of said furnace remote from its input end by gravity, while the gasification gases are extracted by a pressure difference, the gasification gases are passed along the lateral wall of the furnace in a direction opposite to the direction of movement of refuse in the furnace, said gases traversing the externally heated zone of the furnace, and the burnt gasification gases are extracted from the chamber in which the heating of the furnace takes place.

In a preferred embodiment of the invention the refuse is advanced in the furnace from the input zone to the output zone for the cinders by a helix formed in relief on the inside of the lateral wall of the furnace. The walls of the heating chamber which surrounds the furnace are cooled by a circulation of air by means provided by a ventilator, which forces this air into a duct which leads to the chimney. The burned gasification gases are drawn out toward a region of lower pressure at the outlet of a nozzle positioned in the current of air which cools the heating chamber, said burned gases being drawn out by said flow of air and mixed therewith.

It is also an object of the present invention to provide the new article of manufacture which consists of an incinerator for refuse adapted to be used in carrying out the foregoing process. This incinerator is essentially characterized by the fact that it comprises, in the first place, a prismatic or cylindrical furnace having a substantially horizontal axis or a slightly inclined axis about which it rotates, said furnace being provided at one end with means for feeding in refuse to be incinerated and at its other end with openings in its lateral wall, as well as internal means for advancing the refuse from the input end toward the opposite end. The apparatus also comprises a heating chamber encircling said furnace and the openings in its lateral wall, said chamber having at least one heating device which acts on the wall of the furnace and is in communication with the ambient atmosphere through an air inlet duct and through a vent for exhausting burnt gas. The incinerator also comprises external protective means for the wall of the heating chamber and means for rotating the furnace.

In a preferred embodiment of the invention, the furnace is a cylinder which has a helix projecting inwardly from its lateral wall. In alignment with and beneath the openings at one end of the furnace is a passage for evacuating cinders, with a removable cinder box therebeneath. The evacuation passage for the cinders and the cinder box are in communication with the inside of the heating chamber. The duct for admitting air to the heating chamber is provided with an adjustable register. The heating chamber is substantially cylindrical and encircled by two concentric jackets, the outer jacket having an air inlet and the inner jacket being in communication with the interior of the outer jacket near the end thereof remote from said air inlet. The inside of the inner jacket is connected to the suction side of a ventilating fan which directs gas toward the gas outlet chimney. The stream of air produced by the ventilator passes around a nozzle positioned substantially axially of this stream, and pointing in the same direction, said nozzle being connected to the outlet duct for the gases burned in the heating chamber. The heating means for the furnace consists of at least one burner positioned in the heating chamber, the flame of which burner is directed against the lateral wall of the furnace. The furnace is supported at its two ends on rollers, at least one of which is rotated through reduction gearing, said rollers being positioned outside said outer jacket.

In a first embodiment the loading device for the refuse is a stationary feed chute connected to one end of the incinerator furnace. In a second embodiment the loading device is a cylindrical or prismatic pre-dryer rotating about its own axis, said predryer being positioned inside a chamber traversed by the current of heating gases and air which is produced outside the incinerator in the direction of the chimney. The predryer may advantageously have its axis substantially horizontal and comprise an internally projecting helix. It may also be supplied by a screw. The chamber for circulation of heated gases which encircles the predryer may itself be positioned inside a protective jacket.

It will be seen that, by utilizing the incinerating process according to the invention, and the corresponding incinerator, any compaction of the refuse inside the furnace is completely avoided because of the constant rotation of the furnace about its axis. This clearly improves the gasification and combustion conditions for the refuse inside the furnace.

Moreover, the incinerated refuse is evacuated at the end of the furnace remote from the one at which it is introduced as the cinders fall into the cinder-removal passage through the holes provided for this purpose in the lateral wall of the furnace. The cinders are evacuated in the zone of the lower generatrices of the furnace, but the same holes when rotated to the top of the furnace, are used to exhaust the gases of gasification from the interior of the furnace into the heating chamber which encircles the furnace. These gasification gases, which are combustible, thus come into contact with the flame of the burners in the combustion chamber and their total combustion is thus ensured. The calories produced by this combustion add to the calories supplied by the burner for heating the furnace. This arrangement accordingly produces substantial economy in heating because the gasification gases participate in the incineration of the refuse.

The burned gasification gases are evacuated with the combustion gases of the burners through the duct for evacuating burned gases, and this hot gas is sucked from the heating chamber by the partial vacuum which prevails at the outlet of the nozzle positioned in the current of air supplied by the ventilator of the installation. It follows that hot gas is not passed through the ventilator of the installation, which makes it possible to obtain good mechanical strength for this ventilator. It should also be noted that the external cooling of the heating chamber is by circulation of the air which is required to extract the burned gases from the combustion chamber. The thermal efficiency of the installation is still further improved when the incinerator is used in combination with a pre-dryer such as has been already described in connection with the second embodiment, since in this case, before being evacuated through the chimney, the mixture of cooling air and burned gases transfers part of its calories to the refuse to be incinerated so as to ensure a certain drying of this refuse before its introduction into the furnace of the incinerator.

In order that the object of the invention may be better understood, two embodiments thereof will now be described, purely by way of illustration and example, with reference to the accompanying drawings in which:

FIG. 1 is a vertical section taken along the line I I of FIG. 2 showing an incinerator according to the invention;

FIG. 2 is a horizontal cross-section taken along the line 11 II of FIG. 1, but the furnace of the incinerator and its feed chute are not shown in section;

FIG. 3 is an elevational view of the incinerator of FIG. 1 taken along the line III III; and

FIG. 4 shows an incinerator of the type of FIG. 1 associated with a pre-dryer, said pre-dryer being shown in section and the incinerator proper being shown in elevation.

Referring now to the drawings, it will be seen that the incinerator according to the invention comprises a central cylindrical furnace 1 supported by rollers 2 positioned on opposite sides of the cylinder 1, at the bottom of this cylinder, and at each end of the cylinder. One of the four rollers 2 which supports the cylinder 1 is mounted on the same shaft as a sprocket 3 which cooperates with a chain 4 which transmits to the sprocket 3 the rotation of the output gear 5 of reduction gearing 6. The cylindrical furnace l carries on its internal wall a helix 7 which projects into the cylinder. A supply chute 8 is connected to the circular orifice in the furnace l by means of a rotary joint. An orifice in the supply chute 8 remote from its connection to the cylindrical furnace 1 is provided with a cover 9. The end of the furnace l remote from the end at which it is connected to the supply chute 8 is closed by an end member 10 which may be removable to provide a trap for cleaning out the inside of the furnace. The cylindrical furnace 1 has openings 11 in its lateral wall near the end 10 which are regularly spaced about its periphery. The helix 7 which projects inwardly into the cylindrical furnace I extends from the end at which it is attached to the supply chute 8 to the end in which the openings 11 are provided. The helix 7 serves to stiffen the lateral wall of the furnace 1.

Between the chute 8 and the end 10 the furnace is enclosed within a cylindrical wall indicated by reference numeral 12 on the drawings. The wall 12 defines a substantially cylindrical space constituting a heating chamber 13, and the openings 11 in the furnace 1 are inside the chamber 13. The heating chamber 13 comprises at its lower end in alignment with the portion of the furnace in which the openings 11 are provided an outlet duct 14 for cinders positioned in alignment with an ash box 15 located in a seat 16. The front face 15a of the ash box 15 closes the seat 16 and consequently separates it from the space outside the heating chamber 13. The ash box 15 is slidably removable from its seat 16. The heating chamber 13 communicates with the ambient atmosphere through an air inlet duct 17, the outer end of which is closed by a control register 18. The duct 17 is positioned at the lower end of the heating chamber 13 near the passage for evacuating cinders 14. At the upper end of the heating chamber 13 is a duct 19 for evacuating burned gases, which duct communicates with the heating chamber 15 through an orifice near the part of the furnace l at which it is connected to the stationary supply chute 8. The duct 19 has a nozzle 20 at the end remote from that at which it is connected to the heating chamber 15. In a horizontal plane which passes through the axis of the cylindrical furnace 1 is a burner 32 supplied with fuel oil. The flame of this burner penetrates inside the heating chamber 13 through the duct 12a. The flame of the burner 32 is directed against the central part of the lateral wall of the furnace 1.

The wall 12 of the heating chamber 13 is encircled by an inner jacket 21 which is in turn encircled by an outer jacket 22. An annular space is defined between the wall 12 and the inner jacket 21. The inner jacket 21 has at each end an opening which receives the furnace 1. The opening 23 at the same end as the supply chute 8 has substantially the external diameter of the furnace 1, whereas the opening 24 near the end 10 has a diameter greater than the outer diameter of the furnace 1. The inner jacket 21 communicates with the ambient atmosphere through an exhaust duct 25. A ventilating fan 26 driven by an electric motor 27 is positioned on the vertical axis of said suction duct. The ventilator 26 supplies a passageway 28 the axis of which is parallel to the axis of the nozzle 20. The flow of burned gases through the duct 19 and the nozzle 20 is parallel to the stream of gas produced by the ventilator 26. The duct 28 is connected to the outlet chimney for the gases of the installation. Alternatively an auxiliary burner may be provided in the duct 28 downstream of nozzle 20.

The outer jacket 22 also comprises at its ends two openings receiving the ends of the furnace l. The opening 30 at the same end as the supply chute 8 has a diameter greater than the external diameter of the furnace 1 whereas the opening 31 at the same end as the end 10 of the furnace has a diameter substantially equal to the outer diameter of said furnace. The inside of the outer jacket 22 is in communication with the atmosphere through the opening 30 and with the inside of the inner jacket 21 through the opening 24. In other words, the ventilator 26 causes by producing suction through the opening 30, a circulation of air in the annular space which separates the outer jacket 22 from the inner jacket 21, a passage of this air through the opening 24 and then a circulation of said air between the inner jacket 21 and the wall 12 of the heating chamber 13.

When the device which has just been described is placed in operation, the refuse to be incinerated is introduced through the chute 8. This refuse is introduced at one end of the cylindrical furnace l and because of the rotation of this furnace and the presence of the projecting helix 7, the refuse advances progressively toward the end 10. The rotation of the furnace makes it possible to ensure constant stirring of the refuse. The furnace 1 is heated externally by the flame of the burner 32. The heating of the wall of furnace 1 by the burner 32 ensures excellent incineration of the refuse inside the furnace 1 with a preliminary degasification of the volatile materials. The incinerator works better because no compaction of the refuse inside the furnace takes place. By the time the refuse arrives in alignment with the openings 11, it has been totally incinerated, since the wall of the furnace l in the zone of impact of the flame of the burner 32 is brought to substantially 750 C. The incinerated refuse then passes through the openings 11 in the lower part of the furnace 1 and falls through the cinder outlet 14 into the ash box of the incinerator.

The gasification gas from the refuse which is produced inside the furnace 1 is sucked through the openings 11 into the heating chamber 13 and, in this heating chamber, encounters the flame of the burners 32. This gasification gas, which is combustible, bursts into flames in the heating chamber 13 and increases the calories available to heat the wall of the furnace 1. The burned gases from the burner 32 and the gasification gases which have undergone combustion pass through the duct 19 and the nozzle because of the partial vacuum which exists at the orifice of the nozzle 20, and is created by the current of air produced by the ventilator 26 as it flows around the nozzle 20. It follows that, downstream of the nozzle 20, there is, in the duct 28, a mixture of air and burnt gas. When a large quantity of gasification gas is produced inside the furnace 1 the combustion of this gas may not be complete when it reaches the outlet of the nozzle 20, and it may be desirable to provide an auxiliary burner 29 to ensure its complete combustion.

The ventilator 26 which drives air into the duct 28 produces suction inside the duct 25 and ensures circulation of air through the opening 30, the annular space between 22 and 21, the opening 24, and the annular space between 21 and 12. To ensure convenient regulation of the combustion an air inlet duct 17 is provided at the lower end of the heating chamber 13 and the orifice of this duct has an adjustable register 18. The operation of the register 18 makes it possible to control the quantity of air admitted into the heating chamber in dependence, on the one hand, upon the supply to the heater 32 and, on the other hand, the quantity of gasification gas to be burned. Moreover, in front of the ventilator 26, there is an adjustable intake 33 which makes it possible for constant operation of the ventilator to ensure constant suction inside the heating chamber 13 so as to regulate the quantity of air which passes through the annular spaces between the outer jacket 22 and inner jacket 21 and the wall 12 of the heating chamber 13.

It will be notedthat, such an incinerator, has the advantage of benefltting from a saving in combustible gas due to the recovery of the calories resulting from combustion of the gasification gases formed from the incinerated refuse. On the other hand, due to the rotary movement of the furnace 1, any compaction of the refuse is avoided and this facilitates the incineration. Finally, the ventilator 26 of the installation contacts only cooling air and is not in contact with the burned gases, which considerably increases its useful life.

In the alternative embodiment which is illustrated in FIG. 4, the incinerator which has just been described is associated with a pre-dryer. In this embodiment the chute 8 shown on FIGS. 1 to 3 is replaced by a predrying cylinder 34 rotated about its own axis. The cylinder 34 rests on four rollers 35 positioned in pairs at each end of the cylinder 34. One of the rollers 35 is fixed to a sprocket 36 driven by a chain 37 driven by a gear 38 fixed to the output shaft of reduction gearing 6. Inside the cylinder 34 is an inwardly projecting helix 39. One of the ends of the cylinder 34 is inserted into the end of the furnace 1 remote from the end 10 of this furnace. The other end of the cylinder 34 receives the end of supply means 40 which comprises a screw 41. The cylinder 34 has in its lateral wall perforations 42 which are of small diameter. Its central part is enclosed inside a chamber 43 itself enclosed inside a protective jacket 44. The chamber 43 communicates with the ambient air through a duct 45 which is connected to the chimney of the installation. The chamber 43 also communicates through a duct 46 with the duct 28 through which the burned gases and the corresponding cooling air for the previously described incinerator are driven. At the lower end of the chamber 43 is a screw 47 which makes it possible to extract through a duct 48 any particles of refuse which may fall out of the cylinder 34 through the perforations 42. The screw 47 is rotated by a motor 49. In the chamber 43 the gases from the duct 28 which arrive through the duct 46 circulate counter currently to the movement of the refuse inside the cylinder 34. In such a device, the refuse introduced by the screw 4l into the pre-drying cylinder 34 is heated by the evacuation of the burned gases and the cooling air, which leave the incinerator through the duct 28. This heating reduces the moisture content of the refuse and the vapors escape from the cylinder 34 through the perforations 42 and are drawn by the circulation of gas into the duct 45. The drying takes place in a satisfactory manner, since the refuse cannot become compacted because of the rotation of the cylinder 34. The refuse advances in the cylinder 34 in the direction of the furnace 1 due to the action of the inwardly projecting helix 39.

In this alternative embodiment it will be appreciated that the saving in calories is still further improved as compared to the device illustrated on FIGS. 1 to 3, since calories recovered from the gases evacuated from the incinerator are used to dry the refuse.

It will of course be appreciated that the embodiments hereinbefore described have been given purely by way of illustration and example and may be modified as to detail without thereby departing from the basic principles of the invention.

What is claimed is:

1. Method of incinerating refuse which comprises the steps of introducing refuse at one end of a furnace mounted to rotate about its longitudinal axis within the heating chamber of an incinerator, slowly advancing said refuse along said axis, heating the lateral wall of the furnace, gravitationally extracting from the end of said furnace remote from said one end the cinders formed from the refuse incinerated while simultaneously extracting the gasification gases formed by said refuse by suction means, passing said gases along the lateral wall of the furnace in a direction opposite to that in which the refuse is advanced within the furnace, so that said gases pass by the zone of the furnace wall which is externally heated, extracting the burned gases from said incinerator, and cooling the walls of said heating chamber by means of air circulated therepast by a ventilator, which exhausts said air into a chimney.

2. Method of incinerating refuse which comprises the steps of introducing refuse at one end of a furnace mounted to rotate about its longitudinal axis within the heating chamber of an incinerator, slowly advancing said refuse along said axis, heating the lateral wall of the furnace, gravitationally extracting from the end of said furnace remote from said one end the cinders formed from the refuse incinerated while simultaneously extracting the gasification gases formed by said refuse by suction means, passing said gases along the lateral wall of the furnace in a direction opposite to that in which the refuse is advanced within the furnace, so that said gases pass by the zone of the furnace wall which is externally heated, said gasification gases being extracted by creating suction at the output of a nozzle positioned in the path of air which cools the heating chamber, and the burned gases being extracted from said heating chamber by the flow of said air and mixed therewith.

3. Incinerator for refuse which comprises an elongated furnace mounted to rotate about an axis which is more nearly horizontal than vertical, said furnace being connected at its inlet end to means for feeding refuse to be incinerated thereinto and at its outlet end with openings in its lateral wall, together with internal means for advancing the refuse from the input to the outlet end, a heating chamber encircling said furnace and said openings, said heating chamber being equipped with at least one heating means which acts on the wall of the furnace and being in communication with the ambient air through an air inlet duct and through a duct for exhausting burnt gas, said heating chamber being substantially cylindrical and encircled by two concentric jackets, the outer jacket being provided with an air inlet and the interior of the inner jacket being in com-munication with a part of the interior of the outer jacket remote from said air inlet.

4. Incinerator for refuse which comprises an elongated furnace mounted to rotate about an axis which is more nearly horizontal than vertical, said furnace being connected at its inlet end to means for feeding refuse to be incinerated thereinto and at its outlet end with openings in its lateral wall, together with internal means for advancing the refuse from the input to the outlet end, a heating chamber encircling said furnace and said openings, said heating chamber being equipped with at least one heating means which acts on the wall of the furnace and being in communication with the ambient air through an air inlet duct and through a duct for exhausting burnt gas, said heating chamber being encircled by a jacket which is subjected to suction by a ventilating fan which directs its discharge toward a gas-evacuating chimney.

5. Incinerator as claimed in claim 3 in which the interior of the inner jacket is subjected to suction by a ventilating fan which directs its discharge toward a gasevacuating chimney.

6. Incinerator as claimed in claim 5 in which the stream of air produced by the ventilator passes around a nozzle positioned substantially axially of said stream and extending in the same direction, said nozzle being connected to the duct for evacuating burnt gases from the heating chamber.

7. Incinerator as claimed in claim 4 in which the heating means for the furnace comprises at least one burner positioned in the heating chamber, with the flame of said burner directed toward the lateral wall of the furnace.

8. Incinerator as claimed in claim 4 in which the furnace is carried at its two ends on rollers, at least one roller being rotatably driven by a suitable motor, and said rollers being positioned outside said outer jacket.

9. Incinerator as claimed in claim 4 in which the means for feeding refuse is a stationary chute connected to one end of the furnace.

l0. Incinerator as claimed in claim 6 in which the means for feeding refuse consists of an elongated predryer rotatably driven about its own axis, said pre-dryer being positioned inside a chamber traversed by the current of burnt gases and air which is driven from the incinerator in the direction of the chimney.

l1. Incinerator as claimed in claim 10 in which the pre-dryer has a substantially horizontal axis and comprises an inwardly projecting helix.

12. Incinerator as claimed in claim 10 in which the chamber surrounding the pre-dryer through which the burnt gas is circulated is itself located inside a protective jacket.

Patent No. 3,7 5,3 Dated 15 January 197 4 Inventor s JEAN JAGET (Deceased)-PIERRE JAGET (Legal Rep.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

[73] Assigne'e: Claude Agrimonti and Michel Agrimonti Evreux, France Signed and sealed this 23rd day of April 1971 (SEAL) Atte st EDWARD I-I.E*LETCI-BER,JR. G IIARSHALL DAMN y Attesting Officer Commissioner of Patents FQR F USCOMM-DC seen-ps9 N GOVERNMENT PRNU"? OFFICE: [989 0-366-334, 

1. Method of incinerating refuse which comprises the steps of introducing refuse at one end of a furnace mounted to rotate about its longitudinal axis within the heating chamber of an incinerator, slowly advancing said refuse along said axis, heating the lateral wall of the furnace, gravitationally extracting from the end of said furnace remote from said one end the cinders formed from the refuse incinerated while simultaneously extracting the gasification gases formed by said refuse by suction means, passing said gases along the lateral wall of the furnace in a direction opposite to that in which the refuse is advanced within the furnace, so that said gases pass by the zone of the furnace wall whiCh is externally heated, extracting the burned gases from said incinerator, and cooling the walls of said heating chamber by means of air circulated therepast by a ventilator, which exhausts said air into a chimney.
 2. Method of incinerating refuse which comprises the steps of introducing refuse at one end of a furnace mounted to rotate about its longitudinal axis within the heating chamber of an incinerator, slowly advancing said refuse along said axis, heating the lateral wall of the furnace, gravitationally extracting from the end of said furnace remote from said one end the cinders formed from the refuse incinerated while simultaneously extracting the gasification gases formed by said refuse by suction means, passing said gases along the lateral wall of the furnace in a direction opposite to that in which the refuse is advanced within the furnace, so that said gases pass by the zone of the furnace wall which is externally heated, said gasification gases being extracted by creating suction at the output of a nozzle positioned in the path of air which cools the heating chamber, and the burned gases being extracted from said heating chamber by the flow of said air and mixed therewith.
 3. Incinerator for refuse which comprises an elongated furnace mounted to rotate about an axis which is more nearly horizontal than vertical, said furnace being connected at its inlet end to means for feeding refuse to be incinerated thereinto and at its outlet end with openings in its lateral wall, together with internal means for advancing the refuse from the input to the outlet end, a heating chamber encircling said furnace and said openings, said heating chamber being equipped with at least one heating means which acts on the wall of the furnace and being in communication with the ambient air through an air inlet duct and through a duct for exhausting burnt gas, said heating chamber being substantially cylindrical and encircled by two concentric jackets, the outer jacket being provided with an air inlet and the interior of the inner jacket being in com-munication with a part of the interior of the outer jacket remote from said air inlet.
 4. Incinerator for refuse which comprises an elongated furnace mounted to rotate about an axis which is more nearly horizontal than vertical, said furnace being connected at its inlet end to means for feeding refuse to be incinerated thereinto and at its outlet end with openings in its lateral wall, together with internal means for advancing the refuse from the input to the outlet end, a heating chamber encircling said furnace and said openings, said heating chamber being equipped with at least one heating means which acts on the wall of the furnace and being in communication with the ambient air through an air inlet duct and through a duct for exhausting burnt gas, said heating chamber being encircled by a jacket which is subjected to suction by a ventilating fan which directs its discharge toward a gas-evacuating chimney.
 5. Incinerator as claimed in claim 3 in which the interior of the inner jacket is subjected to suction by a ventilating fan which directs its discharge toward a gas-evacuating chimney.
 6. Incinerator as claimed in claim 5 in which the stream of air produced by the ventilator passes around a nozzle positioned substantially axially of said stream and extending in the same direction, said nozzle being connected to the duct for evacuating burnt gases from the heating chamber.
 7. Incinerator as claimed in claim 4 in which the heating means for the furnace comprises at least one burner positioned in the heating chamber, with the flame of said burner directed toward the lateral wall of the furnace.
 8. Incinerator as claimed in claim 4 in which the furnace is carried at its two ends on rollers, at least one roller being rotatably driven by a suitable motor, and said rollers being positioned outside said outer jacket.
 9. Incinerator as claimed in claim 4 in which the means for feeding refuse is a stationary chute connecteD to one end of the furnace.
 10. Incinerator as claimed in claim 6 in which the means for feeding refuse consists of an elongated pre-dryer rotatably driven about its own axis, said pre-dryer being positioned inside a chamber traversed by the current of burnt gases and air which is driven from the incinerator in the direction of the chimney.
 11. Incinerator as claimed in claim 10 in which the pre-dryer has a substantially horizontal axis and comprises an inwardly projecting helix.
 12. Incinerator as claimed in claim 10 in which the chamber surrounding the pre-dryer through which the burnt gas is circulated is itself located inside a protective jacket. 